Hi Luiz,
ke, 2024-12-04 kello 11:58 -0500, Luiz Augusto von Dentz kirjoitti:
> From: Luiz Augusto von Dentz <luiz.von.dentz@xxxxxxxxx>
>
> This reworks hci_cb_list to not use mutex hci_cb_list_lock to avoid bugs
> like the bellow:
This also in principle allows callbacks to be still running on another
CPU when hci_unregister_cb() exits. Not sure if that is unwanted.
>
> BUG: sleeping function called from invalid context at kernel/locking/mutex.c:585
> in_atomic(): 0, irqs_disabled(): 0, non_block: 0, pid: 5070, name: kworker/u9:2
> preempt_count: 0, expected: 0
> RCU nest depth: 1, expected: 0
> 4 locks held by kworker/u9:2/5070:
> #0: ffff888015be3948 ((wq_completion)hci0#2){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3229 [inline]
> #0: ffff888015be3948 ((wq_completion)hci0#2){+.+.}-{0:0}, at: process_scheduled_works+0x8e0/0x1770 kernel/workqueue.c:3335
> #1: ffffc90003b6fd00 ((work_completion)(&hdev->rx_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3230 [inline]
> #1: ffffc90003b6fd00 ((work_completion)(&hdev->rx_work)){+.+.}-{0:0}, at: process_scheduled_works+0x91b/0x1770 kernel/workqueue.c:3335
> #2: ffff8880665d0078 (&hdev->lock){+.+.}-{3:3}, at: hci_le_create_big_complete_evt+0xcf/0xae0 net/bluetooth/hci_event.c:6914
> #3: ffffffff8e132020 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:298 [inline]
> #3: ffffffff8e132020 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:750 [inline]
> #3: ffffffff8e132020 (rcu_read_lock){....}-{1:2}, at: hci_le_create_big_complete_evt+0xdb/0xae0 net/bluetooth/hci_event.c:6915
> CPU: 0 PID: 5070 Comm: kworker/u9:2 Not tainted 6.8.0-syzkaller-08073-g480e035fc4c7 #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
> Workqueue: hci0 hci_rx_work
> Call Trace:
> <TASK>
> __dump_stack lib/dump_stack.c:88 [inline]
> dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
> __might_resched+0x5d4/0x780 kernel/sched/core.c:10187
> __mutex_lock_common kernel/locking/mutex.c:585 [inline]
> __mutex_lock+0xc1/0xd70 kernel/locking/mutex.c:752
> hci_connect_cfm include/net/bluetooth/hci_core.h:2004 [inline]
> hci_le_create_big_complete_evt+0x3d9/0xae0 net/bluetooth/hci_event.c:6939
> hci_event_func net/bluetooth/hci_event.c:7514 [inline]
> hci_event_packet+0xa53/0x1540 net/bluetooth/hci_event.c:7569
> hci_rx_work+0x3e8/0xca0 net/bluetooth/hci_core.c:4171
> process_one_work kernel/workqueue.c:3254 [inline]
> process_scheduled_works+0xa00/0x1770 kernel/workqueue.c:3335
> worker_thread+0x86d/0xd70 kernel/workqueue.c:3416
> kthread+0x2f0/0x390 kernel/kthread.c:388
> ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
> ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243
> </TASK>
>
> Reported-by: syzbot+2fb0835e0c9cefc34614@xxxxxxxxxxxxxxxxxxxxxxxxx
> Closes: https://syzkaller.appspot.com/bug?extid=2fb0835e0c9cefc34614
> Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@xxxxxxxxx>
> ---
> include/net/bluetooth/hci_core.h | 108 ++++++++++++++++++++-----------
> net/bluetooth/hci_core.c | 9 +--
> net/bluetooth/iso.c | 6 ++
> net/bluetooth/l2cap_core.c | 12 ++--
> net/bluetooth/rfcomm/core.c | 6 ++
> net/bluetooth/sco.c | 12 ++--
> 6 files changed, 97 insertions(+), 56 deletions(-)
>
> diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
> index ea798f07c5a2..ca22ead85dbe 100644
> --- a/include/net/bluetooth/hci_core.h
> +++ b/include/net/bluetooth/hci_core.h
> @@ -804,7 +804,6 @@ struct hci_conn_params {
> extern struct list_head hci_dev_list;
> extern struct list_head hci_cb_list;
> extern rwlock_t hci_dev_list_lock;
> -extern struct mutex hci_cb_list_lock;
>
> #define hci_dev_set_flag(hdev, nr) set_bit((nr), (hdev)->dev_flags)
> #define hci_dev_clear_flag(hdev, nr) clear_bit((nr), (hdev)->dev_flags)
> @@ -2017,24 +2016,47 @@ struct hci_cb {
>
> char *name;
>
> + bool (*match) (struct hci_conn *conn);
> void (*connect_cfm) (struct hci_conn *conn, __u8 status);
> void (*disconn_cfm) (struct hci_conn *conn, __u8 status);
> void (*security_cfm) (struct hci_conn *conn, __u8 status,
> - __u8 encrypt);
> + __u8 encrypt);
> void (*key_change_cfm) (struct hci_conn *conn, __u8 status);
> void (*role_switch_cfm) (struct hci_conn *conn, __u8 status, __u8 role);
> };
>
> +static inline void hci_cb_lookup(struct hci_conn *conn, struct list_head *list)
> +{
> + struct hci_cb *cb, *cpy;
> +
> + rcu_read_lock();
> + list_for_each_entry_rcu(cb, &hci_cb_list, list) {
> + if (cb->match && cb->match(conn)) {
> + cpy = kmalloc(sizeof(*cpy), GFP_ATOMIC);
> + if (!cpy)
> + break;
> +
> + *cpy = *cb;
> + INIT_LIST_HEAD(&cpy->list);
> + list_add_rcu(&cpy->list, list);
> + }
> + }
> + rcu_read_unlock();
> +}
> +
> static inline void hci_connect_cfm(struct hci_conn *conn, __u8 status)
> {
> - struct hci_cb *cb;
> + struct list_head list;
> + struct hci_cb *cb, *tmp;
>
> - mutex_lock(&hci_cb_list_lock);
> - list_for_each_entry(cb, &hci_cb_list, list) {
> + INIT_LIST_HEAD(&list);
> + hci_cb_lookup(conn, &list);
> +
> + list_for_each_entry_safe(cb, tmp, &list, list) {
> if (cb->connect_cfm)
> cb->connect_cfm(conn, status);
> + kfree(cb);
> }
> - mutex_unlock(&hci_cb_list_lock);
>
> if (conn->connect_cfm_cb)
> conn->connect_cfm_cb(conn, status);
> @@ -2042,22 +2064,43 @@ static inline void hci_connect_cfm(struct hci_conn *conn, __u8 status)
>
> static inline void hci_disconn_cfm(struct hci_conn *conn, __u8 reason)
> {
> - struct hci_cb *cb;
> + struct list_head list;
> + struct hci_cb *cb, *tmp;
>
> - mutex_lock(&hci_cb_list_lock);
> - list_for_each_entry(cb, &hci_cb_list, list) {
> + INIT_LIST_HEAD(&list);
> + hci_cb_lookup(conn, &list);
> +
> + list_for_each_entry_safe(cb, tmp, &list, list) {
> if (cb->disconn_cfm)
> cb->disconn_cfm(conn, reason);
> + kfree(cb);
> }
> - mutex_unlock(&hci_cb_list_lock);
>
> if (conn->disconn_cfm_cb)
> conn->disconn_cfm_cb(conn, reason);
> }
>
> +static inline void hci_security_cfm(struct hci_conn *conn, __u8 status,
> + __u8 encrypt)
> +{
> + struct list_head list;
> + struct hci_cb *cb, *tmp;
> +
> + INIT_LIST_HEAD(&list);
> + hci_cb_lookup(conn, &list);
> +
> + list_for_each_entry_safe(cb, tmp, &list, list) {
> + if (cb->security_cfm)
> + cb->security_cfm(conn, status, encrypt);
> + kfree(cb);
> + }
> +
> + if (conn->security_cfm_cb)
> + conn->security_cfm_cb(conn, status);
> +}
> +
> static inline void hci_auth_cfm(struct hci_conn *conn, __u8 status)
> {
> - struct hci_cb *cb;
> __u8 encrypt;
>
> if (test_bit(HCI_CONN_ENCRYPT_PEND, &conn->flags))
> @@ -2065,20 +2108,11 @@ static inline void hci_auth_cfm(struct hci_conn *conn, __u8 status)
>
> encrypt = test_bit(HCI_CONN_ENCRYPT, &conn->flags) ? 0x01 : 0x00;
>
> - mutex_lock(&hci_cb_list_lock);
> - list_for_each_entry(cb, &hci_cb_list, list) {
> - if (cb->security_cfm)
> - cb->security_cfm(conn, status, encrypt);
> - }
> - mutex_unlock(&hci_cb_list_lock);
> -
> - if (conn->security_cfm_cb)
> - conn->security_cfm_cb(conn, status);
> + hci_security_cfm(conn, status, encrypt);
> }
>
> static inline void hci_encrypt_cfm(struct hci_conn *conn, __u8 status)
> {
> - struct hci_cb *cb;
> __u8 encrypt;
>
> if (conn->state == BT_CONFIG) {
> @@ -2105,40 +2139,38 @@ static inline void hci_encrypt_cfm(struct hci_conn *conn, __u8 status)
> conn->sec_level = conn->pending_sec_level;
> }
>
> - mutex_lock(&hci_cb_list_lock);
> - list_for_each_entry(cb, &hci_cb_list, list) {
> - if (cb->security_cfm)
> - cb->security_cfm(conn, status, encrypt);
> - }
> - mutex_unlock(&hci_cb_list_lock);
> -
> - if (conn->security_cfm_cb)
> - conn->security_cfm_cb(conn, status);
> + hci_security_cfm(conn, status, encrypt);
> }
>
> static inline void hci_key_change_cfm(struct hci_conn *conn, __u8 status)
> {
> - struct hci_cb *cb;
> + struct list_head list;
> + struct hci_cb *cb, *tmp;
>
> - mutex_lock(&hci_cb_list_lock);
> - list_for_each_entry(cb, &hci_cb_list, list) {
> + INIT_LIST_HEAD(&list);
> + hci_cb_lookup(conn, &list);
> +
> + list_for_each_entry_safe(cb, tmp, &list, list) {
> if (cb->key_change_cfm)
> cb->key_change_cfm(conn, status);
> + kfree(cb);
> }
> - mutex_unlock(&hci_cb_list_lock);
> }
>
> static inline void hci_role_switch_cfm(struct hci_conn *conn, __u8 status,
> __u8 role)
> {
> - struct hci_cb *cb;
> + struct list_head list;
> + struct hci_cb *cb, *tmp;
>
> - mutex_lock(&hci_cb_list_lock);
> - list_for_each_entry(cb, &hci_cb_list, list) {
> + INIT_LIST_HEAD(&list);
> + hci_cb_lookup(conn, &list);
> +
> + list_for_each_entry_safe(cb, tmp, &list, list) {
> if (cb->role_switch_cfm)
> cb->role_switch_cfm(conn, status, role);
> + kfree(cb);
> }
> - mutex_unlock(&hci_cb_list_lock);
> }
>
> static inline bool hci_bdaddr_is_rpa(bdaddr_t *bdaddr, u8 addr_type)
> diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
> index f9e19f9cb5a3..25d180d225c1 100644
> --- a/net/bluetooth/hci_core.c
> +++ b/net/bluetooth/hci_core.c
> @@ -2993,9 +2993,7 @@ int hci_register_cb(struct hci_cb *cb)
> {
> BT_DBG("%p name %s", cb, cb->name);
>
> - mutex_lock(&hci_cb_list_lock);
> - list_add_tail(&cb->list, &hci_cb_list);
> - mutex_unlock(&hci_cb_list_lock);
> + list_add_tail_rcu(&cb->list, &hci_cb_list);
>
> return 0;
> }
> @@ -3005,9 +3003,8 @@ int hci_unregister_cb(struct hci_cb *cb)
> {
> BT_DBG("%p name %s", cb, cb->name);
>
> - mutex_lock(&hci_cb_list_lock);
> - list_del(&cb->list);
> - mutex_unlock(&hci_cb_list_lock);
> + list_del_rcu(&cb->list);
> + synchronize_rcu();
>
> return 0;
> }
> diff --git a/net/bluetooth/iso.c b/net/bluetooth/iso.c
> index 8ed818254dc8..eccdaa16cba0 100644
> --- a/net/bluetooth/iso.c
> +++ b/net/bluetooth/iso.c
> @@ -2154,6 +2154,11 @@ int iso_connect_ind(struct hci_dev *hdev, bdaddr_t *bdaddr, __u8 *flags)
> return HCI_LM_ACCEPT;
> }
>
> +static bool iso_match(struct hci_conn *hcon)
> +{
> + return hcon->type == ISO_LINK || hcon->type == LE_LINK;
> +}
> +
> static void iso_connect_cfm(struct hci_conn *hcon, __u8 status)
> {
> if (hcon->type != ISO_LINK) {
> @@ -2335,6 +2340,7 @@ void iso_recv(struct hci_conn *hcon, struct sk_buff *skb, u16 flags)
>
> static struct hci_cb iso_cb = {
> .name = "ISO",
> + .match = iso_match,
> .connect_cfm = iso_connect_cfm,
> .disconn_cfm = iso_disconn_cfm,
> };
> diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
> index 6544c1ed7143..27b4c4a2ba1f 100644
> --- a/net/bluetooth/l2cap_core.c
> +++ b/net/bluetooth/l2cap_core.c
> @@ -7217,6 +7217,11 @@ static struct l2cap_chan *l2cap_global_fixed_chan(struct l2cap_chan *c,
> return NULL;
> }
>
> +static bool l2cap_match(struct hci_conn *hcon)
> +{
> + return hcon->type == ACL_LINK || hcon->type == LE_LINK;
> +}
> +
> static void l2cap_connect_cfm(struct hci_conn *hcon, u8 status)
> {
> struct hci_dev *hdev = hcon->hdev;
> @@ -7224,9 +7229,6 @@ static void l2cap_connect_cfm(struct hci_conn *hcon, u8 status)
> struct l2cap_chan *pchan;
> u8 dst_type;
>
> - if (hcon->type != ACL_LINK && hcon->type != LE_LINK)
> - return;
> -
> BT_DBG("hcon %p bdaddr %pMR status %d", hcon, &hcon->dst, status);
>
> if (status) {
> @@ -7291,9 +7293,6 @@ int l2cap_disconn_ind(struct hci_conn *hcon)
>
> static void l2cap_disconn_cfm(struct hci_conn *hcon, u8 reason)
> {
> - if (hcon->type != ACL_LINK && hcon->type != LE_LINK)
> - return;
> -
> BT_DBG("hcon %p reason %d", hcon, reason);
>
> l2cap_conn_del(hcon, bt_to_errno(reason));
> @@ -7572,6 +7571,7 @@ void l2cap_recv_acldata(struct hci_conn *hcon, struct sk_buff *skb, u16 flags)
>
> static struct hci_cb l2cap_cb = {
> .name = "L2CAP",
> + .match = l2cap_match,
> .connect_cfm = l2cap_connect_cfm,
> .disconn_cfm = l2cap_disconn_cfm,
> .security_cfm = l2cap_security_cfm,
> diff --git a/net/bluetooth/rfcomm/core.c b/net/bluetooth/rfcomm/core.c
> index ad5177e3a69b..4c56ca5a216c 100644
> --- a/net/bluetooth/rfcomm/core.c
> +++ b/net/bluetooth/rfcomm/core.c
> @@ -2134,6 +2134,11 @@ static int rfcomm_run(void *unused)
> return 0;
> }
>
> +static bool rfcomm_match(struct hci_conn *hcon)
> +{
> + return hcon->type == ACL_LINK;
> +}
> +
> static void rfcomm_security_cfm(struct hci_conn *conn, u8 status, u8 encrypt)
> {
> struct rfcomm_session *s;
> @@ -2180,6 +2185,7 @@ static void rfcomm_security_cfm(struct hci_conn *conn, u8 status, u8 encrypt)
>
> static struct hci_cb rfcomm_cb = {
> .name = "RFCOMM",
> + .match = rfcomm_match,
> .security_cfm = rfcomm_security_cfm
> };
>
> diff --git a/net/bluetooth/sco.c b/net/bluetooth/sco.c
> index 7eb8d3e04ec4..40c4957cfc0b 100644
> --- a/net/bluetooth/sco.c
> +++ b/net/bluetooth/sco.c
> @@ -1397,11 +1397,13 @@ int sco_connect_ind(struct hci_dev *hdev, bdaddr_t *bdaddr, __u8 *flags)
> return lm;
> }
>
> +static bool sco_match(struct hci_conn *hcon)
> +{
> + return hcon->type == SCO_LINK || hcon->type == ESCO_LINK;
> +}
> +
> static void sco_connect_cfm(struct hci_conn *hcon, __u8 status)
> {
> - if (hcon->type != SCO_LINK && hcon->type != ESCO_LINK)
> - return;
> -
> BT_DBG("hcon %p bdaddr %pMR status %u", hcon, &hcon->dst, status);
>
> if (!status) {
> @@ -1416,9 +1418,6 @@ static void sco_connect_cfm(struct hci_conn *hcon, __u8 status)
>
> static void sco_disconn_cfm(struct hci_conn *hcon, __u8 reason)
> {
> - if (hcon->type != SCO_LINK && hcon->type != ESCO_LINK)
> - return;
> -
> BT_DBG("hcon %p reason %d", hcon, reason);
>
> sco_conn_del(hcon, bt_to_errno(reason));
> @@ -1444,6 +1443,7 @@ void sco_recv_scodata(struct hci_conn *hcon, struct sk_buff *skb)
>
> static struct hci_cb sco_cb = {
> .name = "SCO",
> + .match = sco_match,
> .connect_cfm = sco_connect_cfm,
> .disconn_cfm = sco_disconn_cfm,
> };
